The E-BikeKit comes with the motor (the wheel shown in the box) and controller. The battery (the silver tube), charger, and rack came separately.

Beginner

Controls. The motor controller is the little electronic box, usually about the size of a box of wooden matches, that controls your speed. Usually, the controller is mated to the motor, because it has to match with the motor type and voltage. It’s the one component that is a little touchy, and where you’re likely to get failures if you get them at all. Buy your controller and motor together, and make sure they’re right for each other. When you’re assembling your bike, mount the controller in as dry, cool and vibration-free a place as you can, such as on the center tube or luggage rack, and away from the wheels and fenders. One company, Golden Motor, goes so far as to mount their controller inside their hub motors—a great way to protect them from moisture and a good way to ensure a match between the motor and controller.

Rider controls are pretty simple—a throttle, usually a twist-grip or a thumb lever and, sometimes, cutoff switches in the brake levers to ensure you’re not braking against the pull of the motor. A good kit will have rider controls that will blend nicely with the stock controls of the bike.

What’s Available

Each manufacturer has a range of price and power options, as demonstrated in the “Kits” table. One of the best online sources of information is from www.electric-bikes.com, but I leaned heavily on a local dealer, Paul Morlock of Electric Bikes of New England. Not only did he have some great products in stock, but he also had the experience to offer some great advice.

Almost every package is based on products that originate from China, and some suppliers ship directly from China, which can take weeks, if not months, to arrive. You may get great support, or not…there’s no way of knowing. Returning defective parts can become a nightmare. There are several knowledgeable dealers around the United States, that have invested their time and resources to make sure they’re selling you a good product and will back them up.

In ordering my E-BikeKit, which was shipped to me from Electric Bikes of New England, the dealer made a simple mistake—he specified the wrong wheel size, which we didn’t realize until I started the project. A quick call to him and, before I knew it, an order was placed for the correct wheel, to be shipped directly to me. It came the next day, along with a prepaid UPS label to return the first wheel. I also had one technical question and received the answer within 15 minutes of sending my e-mail. Product support is crucial.

Skills & Tools

You’ll need to approach this project with a good understanding of bicycle mechanics, for your own peace of mind, and also for your own safety. You’re mounting some substantial hardware to your bike that can affect its balance and structure. Your gear shifting and braking may be affected, and, especially with the 200 to 1,000 W of additional power, you need to be confident that everything can take the added forces.

If you’re a competent bike mechanic, you should be able to do this. If not, at the very least, take your conversion to a good bike shop for a safety check and tune-up before you hit the road.

No special tools beyond those for basic bike maintenance are usually needed—wrenches for tightening axle nuts, Allen wrenches, screwdrivers, and pliers. It doesn’t hurt to have a multimeter handy. I used mine to check the battery output and connections before connecting the controller, and, if things aren’t working right, you can check continuity. Some wire loom, vinyl electrical tape and insulated heat-shrink tubing (along with a heat gun) will make it a professional-appearing job.

Comments (3)

Quick comment: in the interest of simplification, the author should not have linked "speed" of an ebike motor to battery pack voltage. Peak speed under power is regulated in many countries, and even some areas within a country. Across the US the federal law is the motor assist must kick out at 20mph and the motor may be no larger than 750w (~1hp) to maintain the unlicensed ebike status. Most older systems are 24v, newer are 36v or 48v. Some may be modified to run faster, but the limits are not battery voltage, but the controller electronics and the motor peak wattage/hp.

Thanks for the good info, Mark. Yes, the federal limit is held to 20 mph and 1 hp for commercially-made bikes. But if you make your own ebike, state laws kick in. Here in CA, for example, I can build an ebike from parts or kit, and have a 1,000 W motor, though I am still limited to a max speed of 20 mph from the power system.

Your article is spot on in many ways. I ordered the Chinese kit from "the bay" for around 750 shipped. It's a 1kw golden motors hub with 20ah LifePo4 battery. I got around 1 year use out of it before the battery management system (BMS) failed. The battery is just a bunch of cells wrapped up in duct tape. It does work well though when it runs. I am 300 lbs and can get average 25-30 mph. Would recommend TOP of the line tires and tubes though. I had a front blowout at 25 mph and the road rash wasn't pretty. Also, anything handling power (controller / bms) gets hot. Hang those out in the airstream for cooling. Braking is HUGE when you add all the weight and speed to your bike. I honestly don't feel much difference in wheel braking vs disc. In wet weather I'd go disc. I don't have the controller to give regen a try for braking. I don't recommend rear drive given my setup. Adding disc braking is next to impossible and it was a b!tch to get the freewheel cluster to spin after installation. Clearances were tough to obtain given the chain and frame in high gear. If I were to buy another kit from China, I'd go front wheel drive. I'm hoping top tire makers like Schwalbe realize the need for beefier e-bike tires and develop them. Past 25 mph, you really are asking for it if you have a blowout. A helmet is a definate must, gloves and even other padding case you go down.
All that said, I'd not steer away from e-bikes for a second. They are flat out FUN and I've used mine for short commutes to work on a regular basis. Passing up gas stations daily is a joy you simply have to experience for yourself. I plugged in at work after doing the math for my boss (kill a watt meter helps) how little juice my bike drank. My commute was free at that point. I tow my battery in a well built 2 seat kid trailer. Work stuff and stops by the store go into the trailer. Don't rely on a seat post mounted tote for your 20ah battery unless it's welded steel. My very well made aluminum tote broke inside of 3 months.
Final thoughts, I will probably graduate into a small motorcycle simply for the better tires and brakes. A 48-72v motorcycle will have all the speed / range I need to get to work and our company now has charging stations available so again, my commute will be free. I look forward to leaving gas for good !!